#301.5 damage total, 55.5 damage on most rounds

###Feat selection

###Race selection

###Subclass selection

###Build

##Damage calculation

301.5 damage total, 55.5 damage on most rounds

Feat selection

Race selection

Subclass selection

Build

Damage calculation

#461.5 damage total, 85.5 damage on most rounds

• The Dragonborn's Breath Weapon and the Simic Hybrid's Acid Spit can't even compete with a single GWM attack, so they're out.
• The Fallen Aasimar's Necrotic Shroud (even when applied over the course of the next 4 turns) can't even compete with two GWM attacks, so it's out.
• The Half-Orc's Savage Attacks is irrelevant given our restrictions, so it's out.
• The Centaur's Charge, the Longtooth Shifter's Shifting Feature, and the Minotaur's Goring Rush can't compare to a GMW attack, so they're out.
• The Bugbear's Sneak Attack deals an extra 2d6 at the beginning of combat (assuming surprise), so it's a contender.
• The Variant Human's Feat allows us to reach a +4 strength strength (instead of +3), so it's a contender.

• The Ranger's Companion and Planar Warrior cannot compete with GWM's +20 damage, so Beast Master and Horizon Walker are out.
• Colossus Slayer is strictly superior to Slayer's Prey given that we already have a use for the bonus action and that 1d8 is larger than 1d6, hence Monster Slayer is out.
• Horde Breaker is useless because we are facing a single enemy, Giant killer is also useless because the Barbarian is soaking all the enemy attacks, whereas Colossus Slayer's deals 5d8 over the course of 5 rounds, so it is a contender.
• Dread Ambusher deals a GWM attack and a d8 at the beginning of combat, so it is a contender.

5d8 is less than a GWM attack, so we choose Gloom Stalker.

The total damage over the whole combat is [rounds] * ([2 action attacks] + [1 PM bonus attack]) + [1 Dread Ambusher attack] = 5 * (2 * (1d10 + 20 + 4) + (1d4 + 20 + 4)) + (1d10 + 20 + 4 + 1d8) = 5 * 85.5 + 34 = 461.5.

In that calculation I have not taken reactions into account. If we can guarantee an opportunity attack each round, then the total becomes 5 * (85.5 + [1 opportunity attack]) + 34 = 5 * (85.5 + (1d10 + 20 + 4)) + 34 = 5 * 115.5 + 34 = 609.

#301.5 damage total, 55.5 damage on most rounds

• The Dragonborn's Breath Weapon and the Simic Hybrid's Acid Spit can't even compete with a single GWM attack, so they're out.
• The Half-Orc's Savage Attacks is irrelevant given our restrictions, so it's out.
• The Centaur's Charge, the Longtooth Shifter's Shifting Feature, and the Minotaur's Goring Rush can't compare to a GMW attack, so they're out.
• The Fallen Aasimar's Necrotic Shroud (even when applied over the course of the next 4 turns) can't compete with two GWM attacks, so it's out.
• The Bugbear's Sneak Attack deals an extra 2d6 at the beginning of combat (assuming surprise), so it's a contender.
• The Variant Human's Feat allows us to reach a +4 strength strength (instead of +3), so it's a contender.

• The Ranger's Companion and Planar Warrior cannot compete with a GWM attack, so Beast Master and Horizon Walker are out.
• Colossus Slayer is strictly superior to Slayer's Prey given that we already have a use for the bonus action and that 1d8 is larger than 1d6, so the Monster Slayer is out.
• Horde Breaker is useless because we are facing a single enemy, Giant killer is also useless because the Barbarian is soaking all the enemy attacks, whereas Colossus Slayer's deals 5d8 over the course of 5 rounds, so it is a contender.
• Dread Ambusher deals a GWM attack and a d8 at the beginning of combat, so it is a contender.

5d8 is slightly less than a GWM attack + 1d8, so we choose Gloom Stalker.

The total damage over the whole combat is [rounds] * ([2 action attacks] + [1 PM bonus attack]) + [1 Dread Ambusher attack] = 5 * (2 * (1d10 + 10 + 4) + (1d4 + 10 + 4)) + (1d10 + 10 + 4 + 1d8) = 5 * 55.5 + 24 = 301.5.

In that calculation I have not taken reactions into account. If we can guarantee an opportunity attack each round, then the total becomes [rounds] * ([2 action attacks] + [1 PM bonus attack] + [1 opportunity attack]) + [1 Dread Ambusher attack] = 5 * (39 + 16.5 + (1d10 + 10 + 4)) + 24 = 5 * 75 + 24 = 399.

In that calculation I have not included reaction attacks. If we can guarantee an opportunity attack each round, then the total becomes 5 * (85.5 + [1 opportunity attack]) + 34 = 5 * (85.5 + 1d10 + 20 + 4) + (1d10 + 20 + 4 + 1d8) + 34 = 5 * 115.5 + 34 = 609.

In that calculation I have not taken reactions into account. If we can guarantee an opportunity attack each round, then the total becomes 5 * (85.5 + [1 opportunity attack]) + 34 = 5 * (85.5 + (1d10 + 20 + 4)) + 34 = 5 * 115.5 + 34 = 609.